On-board detection and logging of driver smartphone use

ABSTRACT

Methods and a computer application program for identifying manual use of a phone by the driver of a vehicle. The application collects heading, velocity and radial acceleration data already available to the operating system of all smart phones and uses the asymmetry of Coriolis acceleration with respect to right and left turns to detect manual phone usage by a driver. Detection may result in a visual and auditory warning that would incriminate the driver if the vehicle were to be stopped by law enforcement authorities or involved in an accident.

The present application claims the priority of U.S. Provisional PatentApplication, Ser. No. 63/260,229, filed 12 Aug. 2021, incorporatedherein in its entirety by reference.

TECHNICAL FIELD OF THE INVENTION

The present invention pertains to methods for identifying manual use ofa mobile phone by the driver of a vehicle and to a mobile phone that hasbeen adapted to sense when it is being used by the driver of a vehicle.

BACKGROUND OF THE INVENTION

Whereas in the later decades of the 20^(th) Century significant gains intraffic safety were still achieved through redesign of automobiles andhighways, improvements in safety today require attention to the behaviorand focus of drivers, at least until such a time as autonomous vehiclecontrol becomes pervasive on the highways. To preclude driverdistraction, the use of phones by drivers has been limited by variousgovernment authorities around the world to truly hands-free systemsonly, with loud-speakers or a headset and a fixed microphone installedin the vehicle. Disregard for this provision may have obvious disastrousconsequences, imperilling the operator and others.

Government regulations proscribing inattentive driving, however, aredifficult to enforce using current enforcement techniques. Inparticular, deficiencies of existing techniques have hindered both:

-   -   a quantitative understanding of the extent to which driver        distraction due to mobile device detracts from road safety in        fact; and    -   effective enforcement mechanisms for existing regulations.        Thus, it is currently impossible to ascertain accurately what        fraction of road accidents are attributable to driver        distraction, while current modalities for mitigating driver        distraction by real-time warning are similarly encumbered.

Techniques for identifying smartphone positioning within a vehicle thatare based on empirical sensor response statistics over segmenteditinerary features are summarized by J. Wahlström, “Sensor Fusion forSmartphone-based Vehicle Telematics,” Doctoral Thesis, KTH RoyalInstitute of Technology, pp. 121-43 (2017). More robust data forpurposes of enforcement, litigation, or insurance programs are desirableand are derived in accordance with the present invention taught herein.

SUMMARY OF THE INVENTION

Methods described herein address existing deficiencies by using acombination of capabilities that are already built into the hardware andoperating systems of all smartphones. Embodiments of the presentinvention use external (“Earth-reference-frame-based”) references(magnetometer and GPS) in combination with inertial measurements derivedby the smartphone's own accelerometer(s)

-   -   to discern that a device is being used manually by a driver;    -   to obtain an evidentiary log attesting to the duration of such        use, and, in the worst case, to the time of use relative to the        time of an accident; and    -   to warn the driver that such behavior has been detected and is        illicit.

In accordance with preferred embodiments of the present invention, amethod is provided for detecting manual use of a mobile phone by adriver of a vehicle. The method has steps of:

-   -   a. receiving data associated with a contemporaneous heading and        a contemporaneous speed of the vehicle;    -   b. deriving, based on said data, an incremental heading change,        a sign associated with the incremental heading change that is        one of positive or negative, and a nominal radial acceleration;    -   c. receiving inertial accelerometer data from an accelerometer        onboard the mobile phone;    -   d. calculating, based at least on said inertial accelerometer        data, an actual radial acceleration and an acceleration of the        mobile phone; and    -   e. determining manual use by the driver on the basis of at least        the actual radial acceleration relative to the nominal radial        acceleration.

In further methods in accordance with the present invention, the step ofreceiving data associated with a contemporaneous heading and speed ofthe vehicle may include receiving said data from at least one of amagnetometer and a GPS receiver disposed aboard the mobile phone. Othermethods may also have a step of calculating a signed offset between thenominal radial acceleration and the actual radial acceleration, with thesigned offset having a sign, positive or negative, associated with asense of the incremental heading change. The offset may be an arithmeticdifference or a ratio, or some other function involving the nominalradial acceleration and the actual inertial acceleration of the mobilephone.

In other methods in accordance with the present invention, there is alsoa step of accumulating the signed offset between the nominal radialacceleration and the actual radial acceleration at a plurality ofinstants thereby generating a net signed offset.

The step of determining manual use may be based upon a magnitude of thenet signed offset, and, further, upon transverse walk data.

In yet further embodiments of the invention, there may be a further stepof accumulating the driver to a detected condition of manual use of themobile phone, such as by generating an alarm. Additionally, the dataassociated with the contemporaneous heading and the contemporaneousspeed of the vehicle may be logged.

In accordance with another aspect of the present invention, animprovement is provided to a mobile phone of the type having amagnetometer, a GPS receiver and an accelerometer and used tocommunicate via a network of cells. The improvement is adapted to detectusage of the mobile phone by the driver of a vehicle by virtue ofloading thereon:

-   -   a. program code for receiving data from the magnetometer, the        data associated with a contemporaneous heading and for receiving        a contemporaneous speed of the vehicle derived from GPS data;    -   b. program code for deriving, based on said data, an incremental        heading change, a sign associated with the incremental heading        change that is one of left or right, and a nominal radial        acceleration;    -   c. program code for receiving inertial accelerometer data from        the accelerometer;    -   d. program code for calculating, based at least on said inertial        accelerometer data, an actual radial acceleration and        acceleration of the mobile phone uncorrelated with vehicle        motion;    -   e. program code for calculating, based at least on said inertial        accelerometer data, an actual radial acceleration of the mobile        phone; and    -   e. program code for determining manual use of the mobile phone        on the basis of at least the actual radial acceleration of the        mobile phone relative to the nominal radial acceleration.

In accordance with other embodiments of the present invention, there maybe program code for calculating a signed offset between the nominalradial acceleration and the actual radial acceleration, the signedoffset bearing the sign associated with the incremental heading change.There may additionally, be program code for accumulating a signed offsetbetween the nominal radial acceleration and the actual radialacceleration at a plurality of instants thereby generating a net signedoffset. Further program code may generate an alarm upon determination ofmanual use of the mobile phone by the driver.

In accordance with other embodiments of the invention, the improvementmay also have program code for logging the data associated with thecontemporaneous heading and the contemporaneous speed of the vehicle.

DESCRIPTION OF THE FIGURES

The foregoing features of the invention will be more readily understoodby reference to the following detailed description, taken with referenceto the accompanying drawings, in which:

FIG. 1 depicts a minimum turning radius for a vehicle showing typicaldimensions.

FIG. 2 is a schematic depiction of a course of travel of a vehicle.

FIG. 3 is a flowchart depicting steps in accordance with embodiments ofthe present invention for determining whether a mobile phone is beingused by the driver of a vehicle.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

Adaptation of a mobile phone, in accordance with certain embodiments ofthe present invention, is accomplished by means of an computerapplication program executing methods like those described below, forexample, with reference to FIG. 3 . and referred to hereinafter as “theApplication”. The Application is preferably resident as a non delectableapplication that is preinstalled on smartphones sold for use inparticular jurisdictions and that cannot be disabled by the user. Themobile application registers any lapse of focus by the driver due tomanual use of a smartphone.

For purposes of further description of embodiments of the presentinvention. the following terms shall be subject to the meaningsindicated below, unless otherwise dictated by context.

The term “contemporaneous,” applied to a measured quantity, shall referto data processed substantially concurrently with a measurement andtypically during the course of continuing measurement.

The term “application,” or synonymously, “application program,” refersto a set of steps, however implemented, causing a specific task to beexecuted on a computing or communications device.

An application is referred to as a “background application” on aparticular device when it is not initiated by the user of the deviceand, typically, has no user interface other than, possibly, alerting theuser to the existence of a state or condition.

The term “mobile phone” encompasses any device that may be carried by aperson in any way that serves for both communication and computation.The term includes telephones of the type used to communicate via anetwork of cells, or via satellite, or otherwise.

A change in direction of travel of a vehicle may be assigned a “sign”that is positive for a direction to the right of an immediatelypreceding direction of the vehicle and negative to the left, or,conversely. Whether the turn is to the left or the right constitutes the“sense” of the heading change.

“Heading” denotes the direction of travel of a vehicle.

“Radial” acceleration refers to acceleration of a body, such as avehicle, normal to the direction of a change in heading of the body.

An “inertial accelerometer” is an instrument that senses accelerationrelative to an inertial frame of reference rather than deriving theacceleration from other measured quantities such as velocity, speed ordirection relative to some external frame of reference. One or morephysical sensors may provide the requisite acceleration data, referredto herein as an “actual acceleration” in contradistinction to a nominalacceleration derived by other means.

“Accumulating” data, as the term is used herein, refers to averaging anoffset (a difference or a ratio) over time, with data acquired duringsuccessive turns of the vehicle weighted by the sign assigned to thesense (left or right) of each turn, if any.

An “alarm” denotes any mechanism for signaling to a user the existenceof a condition or state.

A dot placed over a mathematical symbol denotes differentiation withrespect to time. Two dots over a symbol denote two successivederivatives with respect to time.

In accordance with an embodiment of the present invention, theApplication, described in detail in what follows, may run as abackground application until such time as a speed exceeding a thresholdof, say, 30 km/h is detected by the built-in GPS functionality.(Algorithms described below readily discriminate against motion by largevehicles like buses, trains, or planes, such that only motion in apassenger car or small truck will trigger functionality of theApplication.) At that time, and without any voluntary action required onthe part of the driver, the Application enters a Log Active mode,acquiring and recording data from the smartphone's on-board sensors. Inparticular, the Application logs heading (relative to magnetic North)and velocity. The phone's orientation relative to the direction ofmotion is readily derived and any continuing differences betweenacceleration of the device relative to calculated acceleration based onvehicle motion are indicative of manual use of the device.

A mechanism is now described that identifies who is using the device inquestion. Is it the driver, or one of the passengers? That ambiguity hasconfounded existing systems based simply on detecting motion That iswhere the Application comes into play. As staled, heading and velocityare logged on die basis of Earth-frame measurements, allowing a nominalCoriolis acceleration to be calculated and logged as well. Bear in mindthat when a vehicle turns, the outer wheels (driver's side, for a rightturn in the US or European Union) travel faster and further than theinner wheels. That's the purpose of a differential drive, for example.As described in detail below, the Application makes use of theasymmetry, between left- and right-turns, not in wheel speed hut inradial acceleration as sensed by on-board inertia) sensors of asmartphone in question. The Application additionally monitors theacceleration sensed by the three-axis accelerometers (of which asmartphone typically employs two sets for dynamic range andverification) and derives the component of acceleration transverse toboth the direction of travel and the vertical. The discrepancy betweencalculated and measured radial acceleration is accumulated and comparedbetween left- and right-turns. The effect is on the order of up to 10%.Since the driver is further from the center of curvature for turnstoward the passenger's side (i.e., right in the US or European Union),the Application can detect and log manual use by the driver, inparticular. (Type-I errors. i.e.. false positives due to cellphone useby a passenger seated directly behind the driver, turn out to pose aminimal problem, at the level of only a few percent. )

When the Application positively identifies manual phone use by thedriver, the Application may replace the currently active phone screenwith a Warning Screen and emits a Warning Alarm that is intended toprompt the user to put down die phone. If the warning is ignored, anenforcement officer stopping the vehicle (hopefully before any accidentoccurs) will be alerted to the circumstance with no intrusion into theuser's data. That said, if the driver wishes to contest any charges, thedriver may consent to having the data downloaded from the phone andanalyzed or produced in court.

Thus, the Application detects manual cellphone use in a vehicle andidentifies it as pertaining to the driver, and provides a log—ahistorical record—of pertinent motion of the vehicle and of the phonerelative to the vehicle.

From the point of view of the driver of a vehicle, the mere existenceand preinstalled aspect of the Application will naturally deterdangerous manual use of a phone while driving, even if the operation ofthe Application is latent in the background and invisible to the userunless the user is caught handling the phone while driving. Thein-terrorem jeopardy of having one's illicit behavior detected anddocumented would seem to be the strongest argument in favor of adoptingsuch a technology. It deters illegal behavior without requiring theintervention of law enforcement officials.

In the event that law enforcement officials suspect manual use of aphone by a particular driver and stop the vehicle for inspection, aWarning Screen and audio message provide prima facie evidence confirmingtheir suspicion.

The minimum turning radius of a passenger vehicle is typically in therange of 7-8 m, corresponding to as tight a turn as a particular vehicleis capable. The geometry of such a turn is shown in FIG. 1 , based upona graphic published in the American Association of State Highway andTransportation Officials Green Book. (The absence of any turns of radiusof curvature smaller than a specified value provides evidences travel ona larger conveyance than an automobile, such as a bus, train, orairplane.) A bus, for example, cannot execute turns of radius ofcurvature less than about 13-14 m.

Referring to the schematic shown in FIG. 2 , as a vehicle 20 proceedsalong a course of travel 22. it will experience changes in heading θ,here derived by measuring excursions from magnetic North in units ofradians, increasing clockwise. (The sign of changes in heading isspecified arbitrarily within the Application, and both conventions, inthat regard, are within the scope of the present invention as claimed.)Some turns are to the right 23, some turns are to the left 24. (Withoutloss of generality, and for heuristic convenience, it is assumed thatthe Application is being employed in the US or European Union and thatthe driver sits on the left. Thus, the driver sits on the outside of aright turn and the inside of a left turn.)

For purposes of the current document, the term “turn” encompasses anychange Δθ of vehicle heading, whether resulting in a significant changein the direction of travel, or not. The discussion here employs aneffective turn radius TR that is defined as now described. TR is only aproxy for the instantaneous geometrical radius of curvature of vehiclecourse 22, but is, instead, taken over a finite time rather than in theinfinitesimal limit. In the course of an interval of time Δt during aturn, the vehicle travels a distance ΔS=vΔl, where v is the speed of thevehicle. As the heading has shifted Δθ in that interval, the effectiveturn radius

${TR} = {\frac{\Delta S}{\Delta\theta}.}$

A typical turn is now considered, in order to provide the reader with anidea of the magnitudes involved. Referring, again, to FIG. 2 , it isassumed, for example, that vehicle 20 executes a 90° turn 25 in 5 s,traveling at 10 kw/h. If the turn rate

$\overset{.}{\theta} = {\frac{d\theta}{dl} = {\frac{\pi/2}{5} = {\frac{\pi}{10}{rad}/s}}}$

is constant throughout the turn, the distance traveled during the5-second turn is 55 m. The effective turn radius is thus TR=35 m. At anurban street comer, with a comparable 90° turn taken at 10 km/h over 5s, TR=6.75 m.

As the vehicle 20 turns, the radial acceleration α_(θ) contains a termproportional to {umlaut over (θ)}, assumed zero, and a term referred toas the Coriolis term. ˜2v{dot over (θ)}. The vehicle speed v isavailable on a smart phone, as the variable speed in the Core LocationFramework of iOS, on an iPhone™, for example. The Application obtainsthe vehicle speed v from the onboard GPS measurement and the turn rate{dot over (θ)} from time differentiation of the phone's magnetometerheading, and calculates a nominal radial acceleration designated α_(θ)^(⊕). The symbol ⊕ denotes Earth, as the calculated radial accelerationis Earth-frame-based. Both heading and speed are coarse measures of themotion of vehicle 20 and limited by GPS resolution. The radialacceleration calculated in the aforesaid manner is referred to herein asthe “nominal radial acceleration” of the vehicle.

In order to continue developing a sense of the magnitude of the effectused by the Application to detect manual phone usage by a driver, theEarth-frame-based radial acceleration in the above example of a vehicleturning at 40 km/h, is calculated as α_(θ) ^(⊕)≈2×(1.1 m/s)(π/10rad/s≈6.98 m/s²≈0.71 g, where g is the gravitational acceleration at theEarth's surface.

Now, a smart phone also contains within it the capability of actuallymeasuring acceleration in the frame of the phone, returning the vector(α_(x), α_(y), α_(z)) indexed in the frame of the phone. The componentof that acceleration vector transverse to the direction of motion, andthus radial outward with respect to any turn, can be calculated everytime the accelerometer is read, since the orientation of the phone isknown on the basis of gravity vector and magnetometer North, and issimply called by the Application as a vector (CMAcceleration in the CoreMotion Framework in iOS). (Note: the iPhone™, and smart phonesgenerally, have two sets of accelerometers, referred to herein generallyas “the accelerometer.”) Thus, the radial acceleration that is measured,α_(θ) ^(i), may be compared continuously and logged as a ratio withrespect to the nominally calculated α_(θ) ^(⊕). A concomitant advantageof the Application is that, insofar as acceleration is logged, atimestamp is available with respect to any collision.

On average, the ratio

$\frac{a_{\theta}^{i}}{a_{\theta}^{\oplus}}$

remains approximately equal to 1, when suitably smoothed. But, to theextent to which it is larger during periods of vehicle motion when {dotover (θ)}>0 (turning right) than during periods when {dot over (θ)}<0,confidence increases that the phone and its accelerometer are on theleft (i.e., driver's side) of the centerline of the vehicle. We canestimate the magnitude of this effect. On a right turn, the phone in thedriver's hand is ˜½ m more distant from the center of curvature of theturn than the nominal center line of the vehicle, whereas it is ˜½ mcloser to the center of curvature on a left turn. Thus, the magnitude ofthe telltale effect is about 1 m out of a typical turning radius of,say, 10 m or, on the order of 10%. The excursion from 1 (or “unity”) ofthe ratio of

$\frac{a_{\theta}^{i}}{a_{\theta}^{\oplus}}$

is referred to herein as an “offset.” Of course, for computationalconvenience, the difference between the two values, α_(θ) ^(i) and α_(θ)^(⊕), may be tracked instead, and. similarly, accumulated over intervalsof time to reduce noise. Either comutational scheme is within the scopeof the present invention, as are the accumulation and tracking of otherfunctions of α_(θ) ^(i) and α_(θ) ^(⊕).

In the example above, it was determined that α_(θ) ^(⊕)≈0.7 g so aleft/right asymmetry on the order of 10% of that value is being sought,or somewhat less than 0.1 g. For scale, the specified sensitivity of thebuilt-in MPU-6500 accelerometer on an iPhone is 16884 LSB/g, asspecified inhttps://invensense.tdk.com/products/motion-tracking/6-axis/mpu-6500.That is to say that the sought-after effect of cellphone position withinthe vehicle is on the order of 1500 limes the least significant bitreturned from an accelerometer measurement. While there will bestatistical noise, a clear detection of cellphone position is to beexpected after a moderate duration of driving. The continuously updatingmeasure of

$\frac{a_{\theta}^{i}}{a_{\theta}^{\oplus}},$

separately averaged for right and left turns, can be compared with thestandard deviation to establish meaningful statistics. The degree oflocal acceleration of the phone in the plane transverse to the directionof motion (referred to herein as “transverse walk” data) providesfurther evidence that the phone was being handled during the course ofvehicle motion.

Embodiments of the invention are based upon the recognition that theactually measured acceleration transverse to the direction of car traveland perpendicular to gravity is sensitive to where, within a turningvehicle, the acceleration is measured with respect to the right/leftsense of the turn. This is believed to be a novel application of a knownprinciple that can save lives on the roads. For an example from anotherrealm entirely, an expert marksman is said to be able to determinelocation in the northern or southern hemisphere by observing whether thebullet is pulled to the left or the right of the mark due to ananalogous effect.

The left/right determination of phone position is made on the basis ofaccumulating and analyzing GPS, magnetometer and accelerometer dataprovided as parameters by calls to standard ‘methods’ (in the sense ofobject-oriented programming) of smart phone operating systems. Once itis established to a specified degree of certainly that the driver ishandling a phone, the driver's attention is drawn by the phone flashingan Warning Screen and sounding an alert message to the effect thatmanual device use is illegal. “Please stop the car if you wish to usethe phone,” might be an appropriate alert. If the driver then slows thephone, that would be indicated in the logged data on the app. Thismodality serves to keep the driver's focus on the road ahead, but alsoto register a log of any phone use that might cause lapses of attention.Should a collision occur, first responders would encounter a phone witha live screen in an alert mode. Observation of the Warning Screen mightserve as prima facie evidence for administrative offense procedures,although administrative rule-making or legislation might be required inthat regard. The prima facie evidence could be rebutted if the phone'sowner consents, perhaps on the advice of counsel, to provide logged dataregistered on the phone.

The circumstance under which a mobile phone adapted with the Applicationgives rise to a false positive is when a mobile phone device is used bya passenger seated directly behind the driver. That circumstance ispoorly recognized by the protocol described above. To estimate thefrequency of such a circumstance, assume that a fraction, f, of cars onthe road with a single driver additionally carry a single passenger. Forpurposes of estimation, assume that the same fraction f of one-passengercars carry two passengers, and so on, such that the fraction of vehiclesdecreases exponentially with the number of passengers. The averagenumber of persons in passenger vehicles in the United States (based on2017 data) is 1.59. Solving for the fraction f that yields that average.

$\frac{1 + {2f} + {3f^{2}} + {4f^{3}}}{1 + f + f^{2} + f^{3}} = {1.59.}$

one obtains f=0.346. indicating that 66.4% of passenger vehicles carryonly the driver, and that 4 passengers—the only circumstance typicallygiving rise to n passenger seated directly behind the driver—are presentin only 2.74% of cases, unless, perhaps the car serves as a taxi.

Referring to FIG. 3 , a method for detecting driver cellphone use isdescribed as designated generally by numeral 400 using the steps of theApplication.

In the embodiment depicted in FIG. 3 , the Application resides in adormant Background Mode 401 until a velocity exceeding a threshold, suchas 30 km/h, is detected 403. At that point, data are fetched fromrespective GPS, magnetometer and accelerometer hardware onboard thephone 405. This requires, in iOS, for example, a call tostartDeviceMotionUpdates, where the rate of recurrent sampling isspecified. The update rate is typically limited by hardware to about 100s¹, but, subject to physical limitations, may be programmed to optimizesignal-to-noise. If vehicular travel is detected, the Applicationexpunges any previously saved data and, in step 407 begins to collectand save measurements pertinent to the speed and heading of the car aswell as accelerometer data indicating acceleration sensed by theon-board gyroscope(s). The user may be given the option to retain, andeven to upload, previously collected data, if it is germane for anypersonal purpose. It is here that a timestamp is provided of anycollision, relative to which driver focus can be analyzed as a factorcontributing to the collision.

During successive cycles of data collection, though not necessarilysynchronously, a number of derivative values are calculated, in step407, including changes in heading, and the rate of heading change, aneffective turn radius, the projection of acceleration onto the planetransverse to the direction of car motion. At this stage, if no turn isdetected with un effective turn radius below a specified cutoff, it canbe assumed that the vehicle is a large conveyance, such as a bus ortrain or plane, and the program can be reset, accordingly. Data withrespect to transverse acceleration uncorrelated with vehicle motion,herein referred to as Transverse Walk, indicates that the orientation ofthe phone is changing relative to the car, i.e., that the phone is inmanual use.

The Application keeps track of the statistics of acceleration in theplane transverse to car motion, which is indicative of the phone beingheld manually. The inertial offset is calculated, referring to thediscrepancy between a calculated Coriolis acceleration and the value ofradial acceleration actually measured. Since the data based onEarth-frame-referenced measurements (speed, heading) are derived from apredictive filter (such as a Kalman filter) embedded in the phone'soperating system, it will generally reflect the overall course of thevehicle, smoothed to some degree. By contrast, the inertialaccelerometer data reflect where the phone is situated relative to thecenter of curvature of a given turn.

By binning the data, in step 409, according to whether the vehicle ischanging course to the right or left at the present instant, theinertial offset is accumulated and averaged along with data similarlycorresponding either to left 411 or right 413 turns. A comparison, instep 415, determines whether the phone is situated right or left of thevehicle centerline, and, by incorporating the rms of the accumulatedmeasurements, a degree of confidence may be calculated. Based on athreshold confidence level determined during testing, driver use isdeclared 417 and the phone goes into a Warning Mode, with both visualand Audio cues 419 issued to the driver and an admonition to ceasemanual use of the phone. After some period of time, the program revertsto its original state.

The present invention may be embodied in any number of instrumentmodalities. In particular, the information derived from other techniquesmay be used to complement the data derived as taught above. Inalternative embodiments, the disclosed methods for detecting and loggingsmartphone use by a driver may be implemented as a computer programproduct for use with a computer system. Such implementations may includea series of computer instructions fixed on a tangible medium, such as acomputer readable medium (e.g.. a diskette, CD-ROM, ROM, or fixed disk).The series of computer instructions embodies all or part of thefunctionality previously described herein with respect to the system.Those skilled in the art should appreciate that such computerinstructions can be written in a number of programming languages for usewith many computer architectures or operating systems. Furthermore, suchinstructions may be stored in any memory device, such as semiconductor,magnetic, optical or other memory devices, and may be transmitted usingany communications technology, such as optical, infrared, microwave, orother transmission technologies. It is expected that such a computerprogram product may be distributed as a removable medium withaccompanying printed or electronic documentation (e.g., shrink wrappedsoftware), preloaded with a computer system (e.g., on system ROM orfixed disk), or distributed from a server or electronic bulletin boardover the network (e.g., the Internet or World Wide Web). Of course, someembodiments of the invention may be implemented as a combination of bothsoftware (e.g., a computer program product) and hardware. Still otherembodiments of the invention are implemented as entirely hardware, orentirely software (e.g., a computer program product). These and othervariations and modifications are within the scope of the presentinvention as defined in any appended claims.

What is claimed is:
 1. A method for detecting manual use of a mobilephone by a driver of a vehicle, the method comprising: a. receivingcontemporaneous heading data and contemporaneous speed data associatedwith a contemporaneous heading and a contemporaneous speed of thevehicle; b. deriving, based on the contemporaneous heading data and thecontemporaneous speed data, to the exclusion of any accelerometer data,an incremental heading change, a sign associated with the incrementalheading change that is one of positive or negative, and a nominal radialacceleration; c. receiving inertial accelerometer data from anaccelerometer onboard the mobile phone; d. calculating, based at leaston said inertial accelerometer data, an actual radial acceleration ofthe mobile phone; and e. determining manual use by the driver asdistinct from any passenger on the basis of at least the actual radialacceleration of the mobile phone relative to the nominal radialacceleration.
 2. A method in accordance with claim 1, wherein receivingthe data associated with the contemporaneous heading and thecontemporaneous speed of the vehicle includes receiving said data fromat least one of a magnetometer and a GPS receiver disposed aboard themobile phone.
 3. A method in accordance with claim I, further comprisingcalculating a signed offset between the nominal radial acceleration andthe actual radial acceleration, the signed offset bearing the signassociated with a sense of the incremental heading change.
 4. A methodin accordance with claim
 3. wherein the signed offset is the arithmeticdifference between the nominal radial acceleration and the actual radialacceleration.
 5. A method in accordance with claim 3, wherein the signedoffset is a ratio of the nominal radial acceleration and the actualradial acceleration.
 6. A method in accordance with claim 3, furthercomprising accumulating by averaging the signed offset between thenominal radial acceleration and the actual radial acceleration at aplurality of instants thereby generating a net signed offset.
 7. Amethod in accordance with claim 3, wherein the step of determiningmanual use as distinct from any passenger is based upon a magnitude ofthe net signed offset.
 8. A method in accordance with claim 1, whereinthe step of determining manual use as distinct from any passenger isfurther based upon transverse walk data.
 9. A method in accordance withclaim 1, further comprising alerting the driver to a detected conditionof manual use of the mobile phone.
 10. A method in accordance with claim7, wherein alerting the driver includes generating an alarm.
 11. Amethod in accordance with claim 1, further comprising logging the dataassociated with the contemporaneous heading and the contemporaneousspeed of the vehicle.
 12. An improvement to a mobile phone having amagnetometer, a GPS receiver and an accelerometer, the improvementadapted to detect usage of the mobile phone by a driver of a vehicle byvirtue of loading thereon: a. program code for receiving contemporaneousheading and contemporaneous speed data associated with a contemporaneousheading and a contemporaneous speed of the vehicle; b. program code forderiving, based solely on said contemporaneous heading andcontemporaneous speed data, an incremental heading change, a signassociated with the incremental heading change that is one of positiveor negative, and a nominal radial acceleration; c. program code forreceiving inertial accelerometer data from an accelerometer onboard themobile phone; d. program code for calculating, based at least on saidinertial accelerometer data, an actual radial acceleration of the mobilephone; and f. program code for determining manual use by the driver asdistinct from any passenger on the basis of at least the actual radialacceleration of the mobile phone relative to the nominal radialacceleration.
 13. The improvement in accordance with claim 12, furthercomprising program code for calculating a signed offset between thenominal radial acceleration and the actual radial acceleration, thesigned offset bearing the sign associated with the incremental headingchange.
 14. The improvement in accordance with claim 12, furthercomprising program code for accumulating by averaging a signed offsetbetween the nominal radial acceleration and the actual radialacceleration at a plurality of instants thereby generating a net signedoffset.
 15. The improvement in accordance with claim
 12. furthercomprising program code for generating an alarm upon determination ofmanual use of the mobile phone by the driver.
 16. The improvement inaccordance with claim 12, further comprising program code for loggingthe data associated with the contemporaneous heading and thecontemporaneous speed of the vehicle.